Play test is a hard at times at best..
.
These are the ways I do it...
game comes into the shop...we play it, see if we like it.
We move onto friends and family...We play it with persons without an invested interest in the game.
1)Do they get it?
2)They read the rules...work around the problems the rule generate. Puerto Rico gives many people a run in frustration (one of my many favorites)
3) Do they want to play again.
Dinner Game party...We try to have a game party once per month with a couple we just meet that month. (After we make a very sweet proto. not to be confused with the potatoes.)we play the game with them...they think it is off the shelf...they do the rules.
Then the coffee house...free coffee if they play and give Q&A.
But most of it seems to be Gut feeling...do you feel the game means something...Do you turn away and walk.
Do you believe the people who tested?
Well that seem to be the best we can do with what we have.